Effects of Gamma Irradiation of Egg Cells on Macro and Micro Nutrients Composition of the Edible Larval Stage of Cirina forda (Lepidoptera: Saturniidae)

Abstract

The need for diversification of cost-effective enrichment of human diets with macro and micro-nutrients has assumed global concerns. To this end, entomophagy has been advocated as a promising source of these nutrients but such must be predicated on the on optimization of nutritional quality of the selected insect candidates, and that informed this study. To achieve this, freshly laid eggs of Cirina forda exposed to a range of Gamma irradiation doses (0, 10, 20 and 50Gy) and subsequently raised through the edible larval stage on Vitellaria paradoxa plant’s leaves. Proximate, mineral and micro-nutrient analyses of the irradiated matured C.forda larvae were carried out following standard biochemical procedures. The results of proximate analysis showed that egg exposure to Gamma irradiation significantly (P<0.05) increased dry matter and carbohydrate contents, at doses of 20Gy and 50Gy, respectively (41.43±0.01 and 21.50±0.14%, respectively), the amount of crude protein, crude fibre and ash reduced slightly in the C.forda larvae, with exposure to increasing dose of gamma irradiation (from 54.82±0.12 to 50.32±0.09, 3.93±0.11 to 0.05±0.04 and 8.50±0.07 to 6.38±0.11, respectively). The mineral analysis indicated that while, the amounts of Ca and Mn attained significant peaks in larvae whose eggs were exposed to irradiation doses of 50Gy and 10Gy, respectively (36.03±0.01 and 8.27±0.01%, respectively), Gamma irradiation significantly reduced the concentration of Mg, K, and Fe in the insects. The micro-nutrient content of the C.forda was denominated by Leucine, Arginine and Phenylalanine, with highest concentration of 7.20±0.01, 6.86±0.01 and 5.41±0.01%, respectively, and were not significantly (p<0.05) affected by gamma irradiation. These results suggest that gamma irradiation is promising in improving certain nutrition contents of C.forda and may exert a mitigating effect on anti-feedants inherent in the insect species, which need to be investigated urgently.